Display device and method for manufacturing the same

ABSTRACT

A display device includes a plurality of pixels each including a first light emitting element with a first light reflecting layer, a second light emitting element with a second light reflecting layer, and a third light emitting element with a third light reflecting layer, arranged in a two-dimensional matrix. Each of the light emitting elements includes a first electrode, an organic layer, and a second electrode. Grooves that each have a light shielding layer are formed in a boundary region between the light emitting elements. A bottom of the first groove and a bottom of the third groove are located at a position higher than a top surface of the first light reflecting layer. A bottom of the second groove is located at a position higher than a top surface of the second light reflecting layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.15/761,170, filed in the United States Patent and Trademark Office onMar. 19, 2018, which was a 371 application of International PatentApplication No. PCT/JP2016/073096, filed on Aug. 5, 2016, which claimspriority to Japanese Patent Application No. 2015-187573, filed in theJapan Patent Office on Sep. 25, 2015, the entire contents of which areeach incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a display device and a method formanufacturing the display device.

BACKGROUND ART

In recent years, as a display device substituted for a liquid crystaldisplay device, an organic electroluminescence display device(hereinafter, also simply abbreviated as an “organic EL display device”)using an organic electroluminescence element (hereinafter, also simplyabbreviated as an “organic EL element”) has attracted attention. Theorganic EL display device is a self-luminous type, has a characteristicof low power consumption, and is considered to have sufficientresponsiveness even to a high-definition high-speed video signal.Development and commercialization of the organic EL display device forpractical use are keenly proceeding.

In the organic EL display device, high contrast and high colorreproducibility can be realized, for example, by constituting one pixelwith three sub-pixels (light emitting elements) constituted by asub-pixel having a red light emitting layer and constituted by a lightemitting element that emits red light, a sub-pixel having a green lightemitting layer and constituted by a light emitting element that emitsgreen light, and a sub-pixel having a blue light emitting layer andconstituted by a light emitting element that emits blue light.Meanwhile, reduction of a pixel pitch is required for high resolution.However, it becomes more difficult to constitute one pixel with suchthree sub-pixels as the pixel pitch becomes finer.

Therefore, development of a method for forming a white light emittinglayer over all pixels and coloring white light using a color filter,that is, development of technology for constituting one pixel with threekinds of sub-pixels (light emitting elements) of a red sub-pixel(referred to as a “red light emitting element”) obtained by combining alight emitting element having a white light emitting layer (referred toas a “white light emitting element”) and a red color filter, a greensub-pixel (referred to as a “green light emitting element”) obtained bycombining a white light emitting element and a green color filter, and ablue sub-pixel (referred to as a “blue light emitting element”) obtainedby combining a white light emitting element and a blue color filter isproceeding. The white light emitting layer is formed as a continuouslayer over the entire white light emitting element. It is unnecessary toform the red light emitting layer, the green light emitting layer, andthe blue light emitting layer for each sub-pixel. Therefore, the pixelpitch can be fine. In each of the white light emitting elements, thewhite light emitting layer is formed between a first electrode and asecond electrode. The first electrode is formed independently in each ofthe light emitting elements. Meanwhile, the second electrode is commonin each of the light emitting elements.

As technology for improving a light extraction efficiency in a pixelhaving such a configuration, there is technology for amplifying lightemitted from each of light emitting elements by optimizing a cavitystructure in each of the red light emitting element, the green lightemitting element, and the blue light emitting element. Specifically, forexample, as disclosed in Japanese Patent Application Laid-Open No.2009-091223, a light reflecting layer is formed below a first electrodeincluding a transparent electrode, and a second electrode including asemi-light transmitting material and the light reflecting layerconstitute a resonator structure. In addition, light emitted from alight emitting layer is resonated between the light reflecting layer andthe second electrode, and a part of the light is emitted from the secondelectrode.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2009-091223

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

By the way, light emitted from a light emitting layer is propagated inall directions. Therefore, as illustrated in a schematic partialcross-sectional view of FIG. 8, light emitted from a certain lightemitting element (indicated by a thick solid line in FIG. 8) may enter alight emitting element adjacent to the certain light emitting element(referred to as an “adjacent light emitting element” for convenience).Alternatively, multiple reflection occurs inside a display device, andlight emitted from a certain light emitting element may enter anadjacent light emitting element. Note that refer to FIG. 1 for referencenumerals in FIG. 8. As a result, chromaticity of the entire pixels maybe shifted from desired chromaticity.

Therefore, an object of the present disclosure is to provide a displaydevice including a light emitting element having a configuration and astructure hardly causing entry of light into an adjacent light emittingelement, and a method for manufacturing the display device.

Solutions to Problems

In order to achieve the above object, a method for manufacturing adisplay device according to the present disclosure is a method formanufacturing a display device including a plurality of pixels eachincluding a first light emitting element, a second light emittingelement, and a third light emitting element, arranged in atwo-dimensional matrix,

each of the pixels including a lowermost layer/interlayer insulationlayer, a first interlayer insulation layer formed on the lowermostlayer/interlayer insulation layer, a second interlayer insulation layerformed on the first interlayer insulation layer, and an uppermostlayer/interlayer insulation layer,

each of the light emitting elements including:

a first electrode formed on the uppermost layer/interlayer insulationlayer;

an insulation film formed at least on a region of the uppermostlayer/interlayer insulation layer where the first electrode is notformed;

an organic layer formed over the insulation film from above the firstelectrode and including a light emitting layer containing an organiclight emitting material; and

a second electrode formed on the organic layer,

the first light emitting element including a first light reflectinglayer formed on the lowermost layer/interlayer insulation layer,

the second light emitting element including a second light reflectinglayer formed on the first interlayer insulation layer, and

the third light emitting element including a third light reflectinglayer formed on the second interlayer insulation layer, the methodincluding:

(A) forming a lowermost layer/interlayer insulation layer, a patternedfirst interlayer insulation layer, and a patterned second interlayerinsulation layer; then

(B) forming a light reflecting layer on the entire surface and thenpatterning the light reflecting layer to form a first light reflectinglayer on a region of the lowermost layer/interlayer insulation layerwhere a first light emitting element is to be formed, to form a secondlight reflecting layer on a region of the first interlayer insulationlayer where a second light emitting element is to be formed, and to forma third light reflecting layer on a region of the second interlayerinsulation layer where a third light emitting element is to be formed;then

(C) etching at least a portion of the first interlayer insulation layerlocated in a boundary region between the first light emitting elementand the second light emitting element to form a first recess, at thesame time

etching at least a portion of the second interlayer insulation layerlocated in a boundary region between the second light emitting elementand the third light emitting element to form a second recess, and at thesame time

etching at least a portion of the first interlayer insulation layer anda portion of the second interlayer insulation layer located in aboundary region between the first light emitting element and the thirdlight emitting element to form a third recess; then

(D) forming an uppermost layer/interlayer insulation layer on the entiresurface and then flattening the uppermost layer/interlayer insulationlayer to form a first groove, a second groove, and a third groove in aportion of the uppermost layer/interlayer insulation layer above thefirst recess, the second recess, and the third recess, respectively; andthen

(E) forming a light shielding layer inside the first groove, the secondgroove, and the third groove.

In order to achieve the above object, a display device of the presentdisclosure includes a plurality of pixels each including a first lightemitting element, a second light emitting element, and a third lightemitting element, arranged in a two-dimensional matrix.

Each of the pixels includes a lowermost layer/interlayer insulationlayer, a first interlayer insulation layer formed on the lowermostlayer/interlayer insulation layer, a second interlayer insulation layerformed on the first interlayer insulation layer, and an uppermostlayer/interlayer insulation layer.

Each of the light emitting elements includes:

a first electrode formed on the uppermost layer/interlayer insulationlayer;

an insulation film formed at least on a region of the uppermostlayer/interlayer insulation layer where the first electrode is notformed;

an organic layer formed over the insulation film from above the firstelectrode and including a light emitting layer containing an organiclight emitting material; and

a second electrode formed on the organic layer.

The first light emitting element includes a first light reflecting layerformed on the lowermost layer/interlayer insulation layer.

The second light emitting element includes a second light reflectinglayer formed on the first interlayer insulation layer.

The third light emitting element includes a third light reflecting layerformed on the second interlayer insulation layer.

The uppermost layer/interlayer insulation layer covers the lowermostlayer/interlayer insulation layer, the first light reflecting layer, thesecond light reflecting layer, and the third light reflecting layer.

A first groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the first lightemitting element and the second light emitting element.

A second groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the second lightemitting element and the third light emitting element.

A third groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the first lightemitting element and the third light emitting element.

A light shielding layer is formed inside the first groove, the secondgroove, and the third groove.

A lowermost portion of a bottom of the first groove and a lowermostportion of a bottom of the third groove are located at a position higherthan a top surface of the first light reflecting layer.

A lowermost portion of a bottom of the second groove is located at aposition higher than a top surface of the second light reflecting layer.

Effects of the Invention

In the method for manufacturing a display device according to thepresent disclosure, in step (E), a light shielding layer is formedinside the first groove, the second groove, and the third groove. Inaddition, in the display device of the present disclosure, a lightshielding layer is formed inside the first groove, the second groove,and the third groove. Therefore, it is possible to manufacture a displaydevice hardly causing entry of light into an adjacent light emittingelement. Furthermore, in step (D), an uppermost layer/interlayerinsulation layer is formed on the entire surface, and then the uppermostlayer/interlayer insulation layer is flattened. The first groove, thesecond groove, and the third groove can be thereby formed by a so-calledself-alignment method. Therefore, a light emitting element can bemicronized. In addition, in the display device of the presentdisclosure, a relationship between a lowermost portion of a bottom of agroove and the height of a top surface of a light reflecting layer isdefined. Therefore, it is possible to reliably prevent contact betweenthe groove and the light reflecting layer. Contact between the grooveand the light reflecting layer changes capacitance of a light emittingelement. As a result, variation in luminescent color and brightness mayoccur. Note that effects described herein are merely illustrative andare not restrictive. In addition, an additional effect may be present.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic partial cross-sectional view of a display deviceof Example 1.

FIGS. 2A, 2B, and 2C are schematic partial end views of a lowermostlayer/interlayer insulation layer and the like for describing a methodfor manufacturing the display device of Example 1.

FIGS. 3A and 3B are schematic partial end views of a lowermostlayer/interlayer insulation layer and the like for describing the methodfor manufacturing the display device of Example 1, following FIG. 2C.

FIGS. 4A and 4B are schematic partial end views of a lowermostlayer/interlayer insulation layer and the like for describing the methodfor manufacturing the display device of Example 1, following FIG. 3B.

FIGS. 5A and 5B are schematic partial end views of a lowermostlayer/interlayer insulation layer and the like for describing the methodfor manufacturing the display device of Example 1, following FIG. 4B.

FIG. 6 is a schematic partial end view of a lowermost layer/interlayerinsulation layer and the like for describing the method formanufacturing the display device of Example 1, following FIG. 5B.

FIG. 7 is a schematic partial cross-sectional view of a display deviceof Example 2.

FIG. 8 is a schematic partial cross-sectional view of a display devicefor describing a problem of a conventional display device.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present disclosure will be described on the basis ofExamples with reference to the drawings. However, the present disclosureis not limited to Examples, and various numerical values and materialsin Examples are illustrative. Note that description will be made in thefollowing order.

1. General description on display device of the present disclosure andmethod for manufacturing the display device

2. Example 1 (display device of the present disclosure and method formanufacturing the display device)

3. Example 2 (modification of Example 1)

4. Example 3 (modification of Example 1)

5. Others

<General Description on Display Device of the Present Disclosure andMethod for Manufacturing the Display Device>

In the following description, a laminated structure of a firstinterlayer insulation layer, a second interlayer insulation layer, andan uppermost layer/interlayer insulation layer may be referred to as an“interlayer insulation layer/laminated structure” for convenience.

In the method for manufacturing a display device according to thepresent disclosure, in step (C), a portion of a lowermostlayer/interlayer insulation layer and a portion of a first interlayerinsulation layer located in a boundary region between a first lightemitting element and a second light emitting element may be etched toform a first recess, at the same time

a portion of the first interlayer insulation layer and a portion of asecond interlayer insulation layer located in a boundary region betweenthe second light emitting element and a third light emitting element maybe etched to form a second recess, and at the same time

a portion of the lowermost layer/interlayer insulation layer, a portionof the first interlayer insulation layer, and a portion of the secondinterlayer insulation layer located in a boundary region between thefirst light emitting element and the third light emitting element may beetched to form a third recess.

In the method for manufacturing a display device according to thepresent disclosure including the above preferable form,

a lowermost portion of a bottom of a first groove and a lowermostportion of a bottom of a third groove may be located at a positionhigher than a top surface of a first light reflecting layer, and

a lowermost portion of a bottom of a second groove may be located at aposition higher than a top surface of a second light reflecting layer.

In the method for manufacturing a display device according to thepresent disclosure including the above preferable form or the displaydevice of the present disclosure,

a lowermost portion of a bottom of a first groove and a lowermostportion of a bottom of a third groove may be located at a positioncloser to a first light emitting element than a third light emittingelement, and

a lowermost portion of a bottom of a second groove may be located at aposition closer to a second light emitting element than the third lightemitting element.

In the display device of the present disclosure including the abovevarious preferable forms or a display device obtained by the method formanufacturing a display device according to the present disclosure(hereinafter, these may be collectively referred to as “the displaydevice or the like of the present disclosure”), specific examples of alight shielding material constituting a light shielding layer include amaterial capable of shielding light, such as titanium (Ti), chromium(Cr), tungsten (W), tantalum (Ta), aluminum (Al), or MoSi₂. The lightshielding layer can be formed by a vapor deposition method including anelectron beam vapor deposition method, a hot filament vapor depositionmethod, and a vacuum vapor deposition method, a sputtering method, a CVDmethod, an ion plating method, or the like.

In the display device or the like of the present disclosure, the groovemay be formed so as to surround a light emitting element. The groove isformed by a so-called self-alignment method. The groove does not have tobe completely filled with the light shielding layer. That is, the lightshielding layer only needs to cover at least a side surface and a bottomof the groove. The light shielding layer may be in contact with a firstelectrode. Alternatively, the light shielding layer may be grounded. Thefirst light reflecting layer constituting the first light emittingelement may be electrically connected to the first electrodeconstituting the first light emitting element. The second lightreflecting layer constituting the second light emitting element may beelectrically connected to the first electrode constituting the secondlight emitting element. The third light reflecting layer constitutingthe third light emitting element may be electrically connected to thefirst electrode constituting the third light emitting element.Alternatively, each light reflecting layer may be grounded.

The insulation film may be formed on a region of the upperlayer/interlayer insulation layer where the first electrode is notformed and at an edge of the first electrode. That is, the insulationfilm may be formed on the uppermost layer/interlayer insulation layerand the first electrode, an opening may be formed in the insulation filmon the first electrode, and the first electrode may be exposed to abottom of the opening. The organic layer is formed over the insulationfilm from above the first electrode exposed to a bottom of the opening.Alternatively, the insulation film may be formed on the uppermostlayer/interlayer insulation layer exposed between the first electrodeand the first electrode. The organic layer is formed over the insulationfilm from above the first electrode. A material constituting theinsulation film and a material constituting the uppermostlayer/interlayer insulation layer may be the same as or different fromeach other.

The display device or the like of the present disclosure may beconstituted by an organic electroluminescence display device (organic ELdisplay device). The light emitting element may be constituted by anorganic electroluminescence element (organic EL element). In addition,the lowermost layer/interlayer insulation layer, the interlayerinsulation layer/laminated structure, the organic layer, and the secondelectrode may be common in the plurality of light emitting elements.

In the light emitting element in the present disclosure, the lightemitting layer may be constituted by at least two light emitting layersthat emit different colors. In this case, light emitted from the organiclayer may be white. Specifically, the light emitting layer may have astructure obtained by laminating three layers of a red light emittinglayer that emits red light (wavelength: 620 nm to 750 nm), a green lightemitting layer that emits green light (wavelength: 495 nm to 570 nm),and a blue light emitting layer that emits blue light (wavelength: 450nm to 495 nm), and emits white light as a whole. Alternatively, thelight emitting layer may have a structure obtained by laminating twolayers of a blue light emitting layer that emits blue light and a yellowlight emitting layer that emits yellow light, and emits white light as awhole. Alternatively, the light emitting layer may have a structureobtained by laminating two layers of a blue light emitting layer thatemits blue light and an orange light emitting layer that emits orangelight, and emits white light as a whole. In addition, such a white lightemitting element that emits white light includes a red color filter toconstitute a red light emitting element. The white light emittingelement includes a green color filter to constitute a green lightemitting element. The white light emitting element includes a blue colorfilter to constitute a blue light emitting element. In addition, onepixel is constituted by a red light emitting element, a green lightemitting element, and a blue light emitting element. In some cases, onepixel may be constituted by a red light emitting element, a green lightemitting element, a blue light emitting element, and a light emittingelement that emits white light (or a light emitting element that emitscomplementary color light). Note that, in a mode constituted by at leasttwo light emitting layers that emit light of different colors, there isactually a case where the light emitting layers that emit light ofdifferent colors are mixed and are not clearly separated into thelayers.

The color filter is constituted by a resin to which a coloring agentcontaining a desired pigment or dye is added. By selecting a pigment ora dye, adjustment is performed such that light transmittance in a targetwavelength range of red, green, blue, or the like is high, and lighttransmittance in the other wavelength ranges is low. In a light emittingelement that emits white light, it is only required to dispose atransparent filter. A black matrix layer may be formed between a colorfilter and a color filter. For example, the black matrix layer isconstituted by a black resin film (specifically, including a blackpolyimide resin, for example) having an optical density of 1 or more,mixed with a black coloring agent, or a thin film filter usinginterference of a thin film. The thin film filter is formed bylaminating two or more thin films including metal, metal nitride, ormetal oxide, for example, and attenuates light by utilizing interferenceof a thin film. Specific examples of the thin film filter include a thinfilm filter obtained by alternately laminating Cr and chromium (III)oxide (Cr₂O₃).

Although not limited, a transistor (specifically, for example, a MOSFET)formed on a silicon semiconductor substrate may be disposed below thelowermost layer/interlayer insulation layer, and the transistor formedon the silicon semiconductor substrate may be connected to the firstelectrode via a contact hole (contact plug) formed in the lowermostlayer/interlayer insulation layer and the interlayer insulationlayer/laminated structure. Alternatively, TFTs disposed on varioussubstrates may be disposed below the lowermost layer/interlayerinsulation layer. In this way, the first electrode is disposed on theinterlayer insulation layer/laminated structure, as described above. Inaddition, the lowermost layer/interlayer insulation layer covers a lightemitting element driving unit formed on the first substrate. The lightemitting element driving unit is constituted by one or more transistors(for example, MOSFET or TFT). The transistors are electrically connectedto the first electrode via a contact hole disposed in the lowermostlayer/interlayer insulation layer and the interlayer insulationlayer/laminated structure, as described above. The light emittingelement driving unit can have a known circuit configuration.

In another expression, the display device or the like of the presentdisclosure includes a first substrate, a second substrate, and an imagedisplay unit sandwiched by the first substrate and the second substrate.In the image display unit, a plurality of the light emitting elements inthe present disclosure including the preferable forms and configurationsdescribed above is arranged in a two-dimensional matrix. Herein, thelight emitting elements are formed on a side of the first substrate.

In addition, the display device or the like of the present disclosure isa top emission type display device that emits light from the secondsubstrate. In the top emission type display device, it is only requiredto form a color filter and a black matrix layer on a surface side of thesecond substrate opposed to the first substrate. Alternatively, a colorfilter may be formed on a surface side of the first substrate opposed tothe second substrate. That is, an on-chip color filter (OCCF) may beformed on the first substrate. In the display device or the like of thepresent disclosure, in a case where one pixel (or sub-pixel) isconstituted by one light emitting element, examples of arrangement ofpixels (or sub-pixels) include stripe arrangement, diagonal arrangement,delta arrangement, stripe arrangement, and rectangle arrangementalthough not being limited thereto. In addition, in a form in which onepixel (or sub-pixel) is constituted by assembly of a plurality of lightemitting elements (display elements), examples of arrangement of a pixel(or sub-pixel) include stripe arrangement although not being limitedthereto.

In addition to the silicon semiconductor substrate, the first substrateor the second substrate may be constituted by a high strain point glasssubstrate, a soda glass (Na₂O.CaO.SiO₂) substrate, a borosilicate glass(Na₂O.B₂O₃.SiO₂) substrate, a forsterite (2MgO.(SiO₂) substrate, a leadglass (Na₂O.PbO.SiO₂) substrate, various glass substrates each having aninsulation material layer formed on a surface thereof, a quartzsubstrate, a quartz substrate having an insulation material layer formedon a surface thereof, or an organic polymer such as polymethylmethacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl phenol (PVP),polyether sulfone (PES), polyimide, polycarbonate, or polyethyleneterephthalate (PET) (having a form of a polymer material such as aplastic film, a plastic sheet, or a plastic substrate constituted by apolymer material and having flexibility). Materials constituting thefirst substrate and the second substrate may be the same as or differentfrom each other. However, in the top emission type display device, thesecond substrate needs to be transparent to light emitted from the lightemitting element.

In a case where the first electrode functions as an anode electrode,examples of a material constituting the first electrode include varioustransparent conductive materials such as a transparent conductivematerial including, for a base layer, indium oxide, indium-tin oxide(ITO, including Sn-doped In₂O₃, crystalline ITO, and amorphous ITO),indium zinc oxide (IZO), indium-gallium oxide (IGO), indium-dopedgallium-zinc oxide (IGZO, In—GaZnO₄), IFO (F-doped In₂O₃), ITiO(Ti-doped In₂O₃), InSn, InSnZnO, tin oxide (SnO₂), ATO (Sb-doped SnO₂),FTO (F-doped SnO₂), zinc oxide (ZnO), aluminum oxide-doped zinc oxide(AZO), gallium-doped zinc oxide (GZO), B-doped ZnO, AlMgZnO (aluminumoxide and magnesium oxide-doped zinc oxide), antimony oxide, titaniumoxide, NiO, spinel type oxide, oxide having a YbFe₂O₄ structure, galliumoxide, titanium oxide, niobium oxide, nickel oxide, or the like. Thethickness of the first electrode may be 0.01 μm to 0.1 μm, for example.

Meanwhile, in a case where the second electrode is caused to function asa cathode electrode, a material constituting the second electrode (asemi-light transmitting material or a light transmitting material) isdesirably constituted by a conductive material having a small workfunction value so as to be able to transmit emitted light and inject anelectron into an organic layer efficiently. Examples of the materialconstituting the second electrode include a metal having a small workfunction and an alloy thereof, such as aluminum (Al), silver (Ag),magnesium (Mg), calcium (Ca), sodium (Na), strontium (Sr), an alkalimetal or an alkaline earth metal and silver (Ag) [for example, an alloyof magnesium (Mg) and silver (Ag) (Mg—Ag alloy)], an alloy ofmagnesium-calcium (Mg—Ca alloy), or an alloy of aluminum (Al) andlithium (Li) (Al—Li alloy). Among these materials, an Mg—Ag alloy ispreferable, and a volume ratio between magnesium and silver may beMg:Ag=5:1 to 30:1, for example. Alternatively, as a volume ratio betweenmagnesium and calcium may be Mg:Ca=2:1 to 10:1, for example. Thethickness of the second electrode may be 4 nm to 50 nm, preferably 4 nmto 20 nm, and more preferably 6 nm to 12 nm, for example. Alternatively,the second electrode may have a laminated structure of the abovematerial layer and a so-called transparent electrode (for example,thickness 3×10 ⁻⁸ m to 1×10⁻⁶ m) including, for example, ITO or IZO. Abus electrode (auxiliary electrode) including a low resistance materialsuch as aluminum, an aluminum alloy, silver, a silver alloy, copper, acopper alloy, gold, or a gold alloy may be disposed in the secondelectrode to reduce resistance as the whole second electrode. Averagelight transmittance of the second electrode is 50% to 90%, andpreferably 60% to 90%.

Examples of a method for forming the first electrode or the secondelectrode include a combination of a vapor deposition method includingan electron beam vapor deposition method, a hot filament vapordeposition method, and a vacuum vapor deposition method, a sputteringmethod, a chemical vapor deposition method (CVD method), an MOCVDmethod, and an ion plating method with an etching method; variousprinting methods such as a screen printing method, an inkjet printingmethod, and a metal mask printing method; a plating method (anelectroplating method or an electroless plating method); a lift-offmethod; a laser ablation method; and a sol-gel method. According tovarious printing methods and a plating method, the first electrode orthe second electrode having a desired shape (pattern) can be formeddirectly. Note that, in a case where the second electrode is formedafter the organic layer is formed, the second electrode is preferablyformed particularly on the basis of a film formation method in whichenergy of film formation particles is small, such as a vacuum vapordeposition method, or a film formation method such as an MOCVD methodfrom a viewpoint of preventing the organic layer from being damaged.When the organic layer is damaged, non-light emitting pixels (ornon-light emitting sub-pixels) called “dark spots” due to generation ofa leak current may be generated. Furthermore, processes from formationof the organic layer to formation of these electrodes are preferablyperformed without exposure thereof to the atmosphere from a viewpoint ofpreventing deterioration of the organic layer due to moisture in theatmosphere. As described above, the second electrode is preferably aso-called common electrode without being patterned.

Examples of materials constituting the light reflecting layer, the firstlight reflecting layer, the second light reflecting layer, and the thirdlight reflecting layer include aluminum, an aluminum alloy (for example,Al—Nd or Al—Cu), an Al/Ti laminated structure, an Al—Cu/Ti laminatedstructure, chromium (Cr), silver (Ag), and a silver alloy (for example,Ag—Pd—Cu or Ag—Sm—Cu). The light reflecting layer, the first lightreflecting layer, the second light reflecting layer, and the third lightreflecting layer can be formed, for example, by a vapor depositionmethod including an electron beam vapor deposition method, a hotfilament vapor deposition method, and a vacuum vapor deposition method,a sputtering method, a CVD method, an ion plating method; a platingmethod (an electroplating method or an electroless plating method); alift-off method; a laser ablation method; a sol-gel method or the like.

The organic layer includes a light emitting layer containing an organiclight emitting material. Specifically, for example, the organic layermay be constituted by a laminated structure of a hole transport layer, alight emitting layer, and an electron transport layer, a laminatedstructure of a hole transport layer and a light emitting layer servingalso as an electron transport layer, a laminated structure of a holeinjection layer, a hole transport layer, a light emitting layer, anelectron transport layer, and an electron injection layer or the like.Examples of a method for forming the organic layer include a physicalvapor deposition method (PVD method) such as a vacuum vapor depositionmethod; a printing method such as a screen printing method or an inkjetprinting method; a laser transfer method in which an organic layer on alaser absorption layer is separated by irradiating a laminated structureof a laser absorption layer and an organic layer formed on a transfersubstrate with a laser and the organic layer is transferred; and variouscoating methods. In a case where the organic layer is formed on thebasis of the vacuum vapor deposition method, for example, using aso-called metal mask, the organic layer can be obtained by depositing amaterial that has passed through an aperture disposed in the metal mask,or the organic layer may be formed on the entire surface without beingpatterned, as described above. In some cases, at least a part of a partof the organic layer (specifically, for example, a hole transport layer)may be discontinuous at an end of the insulation film.

An insulating or conductive protective film is preferably disposed abovethe second electrode in order to prevent moisture from reaching theorganic layer. The protective film is preferably formed particularly onthe basis of a film formation method in which the energy of filmformation particles is small, such as a vacuum vapor deposition method,or a film formation method such as a CVD method or an MOCVD methodbecause an influence on a base can be reduced. Alternatively, in orderto prevent reduction in brightness due to deterioration of the organiclayer, a film formation temperature is desirably set to roomtemperature. Furthermore, in order to prevent peeling of the protectivefilm, the protective film is desirably formed under a conditionminimizing a stress of the protective film. In addition, the protectivefilm is preferably formed without exposure of an already formedelectrode to the atmosphere. As a result, deterioration of the organiclayer due to moisture or oxygen in the atmosphere can be prevented.Furthermore, the protective film is desirably constituted by a materialthat transmits light generated in the organic layer by, for example, 80%or more. Specific examples of the material include an inorganicamorphous insulating material such as the following materials. Such aninorganic amorphous insulating material does not generate grains, andtherefore has low water permeability and constitutes a good protectivefilm. Specifically, as a material constituting the protective film, amaterial that is transparent to light emitted from the light emittinglayer, is dense, and does not transmit moisture is preferably used. Morespecific examples of the material include amorphous silicon (α-Si),amorphous silicon carbide (α-SiC), amorphous silicon nitride(α-Si_(1-x)N_(x)), amorphous silicon oxide (α-Si_(1-y)O_(y)), amorphouscarbon (α-C), amorphous silicon oxide/nitride (α-SiON), and Al₂O₃. In acase where the protective film is constituted by a conductive material,the protective film is only required to be constituted by a transparentconductive material such as ITO, IZO, or IGZO. The protective film andthe second substrate are bonded to each other, for example, via a resinlayer (sealing resin layer). Examples of a material constituting theresin layer (sealing resin layer) include a thermosetting adhesive suchas an acrylic adhesive, an epoxy-based adhesive, a urethane-basedadhesive, a silicone-based adhesive, or a cyanoacrylate-based adhesive,and an ultraviolet curable adhesive.

On an outermost surface that emits light in the display device (outersurface of the second substrate), an ultraviolet absorbing layer, acontamination preventing layer, a hard coat layer, and an antistaticlayer may be formed, or a protective member may be disposed.

In the display device or the like of the present disclosure, examples ofan insulating material constituting the lowermost layer/interlayerinsulation layer, the interlayer insulation layer/laminated structure,or the insulation film include a SiO_(x)-based material (materialconstituting a silicon-based oxide film) such as SiO₂, non-dopedsilicate glass (NSG), borophosphosilicate glass (BPSG), PSG, BSG, AsSG,SbSG, PbSG, spin on glass (SOG), low temperature oxide (LTO, lowtemperature CVD-SiO₂), low melting point glass, or glass paste; aSiN-based material including a SiON-based material; SiOC; SiOF; andSiCN. Examples of the insulating material further include an inorganicinsulating material such as titanium oxide (TiO₂), tantalum oxide(Ta₂O₅), aluminum oxide (Al₂O₃), magnesium oxide (MgO), chromium oxide(CrO_(x)), zirconium oxide (ZrO₂), niobium oxide (Nb₂O₅), tin oxide(SnO₂), or vanadium oxide (VO_(x)). Examples of the insulating materialfurther include various resins such as a polyimide-based resin, anepoxy-based resin, and an acrylic resin; and a low dielectric constantinsulating material such as SiOCH, organic SOG, or a fluorine-basedresin (for example, a material having a relative dielectric constant k(=ε/ε₀) of 3.5 or less, and specific examples thereof includefluorocarbon, cycloperfluorocarbon polymer, benzocyclobutene, cyclicfluororesin, polytetrafluoroethylene, amorphous tetrafluoroethylene,polyaryl ether, fluorinated aryl ether, fluorinated polyimide, amorphouscarbon, parylene (polyparaxylylene), and fluorinated fullerene).Examples of the insulating material further include Silk (trademark ofThe Dow Chemical Co., coating type low dielectric constant interlayerinsulation film material) and Flare (trademark of Honeywell ElectronicMaterials Co., polyallyl ether (PAE)-based material). In addition, thesematerials can be used singly or in appropriate combination thereof. Theinterlayer insulation layer or the insulation film can be formed by aknown method such as various CVD methods, various coating methods,various PVD methods including a sputtering method and a vacuum vapordeposition method, various printing methods such as a screen printingmethod, a plating method, an electrodeposition method, an immersionmethod, or a sol-gel method.

In order to further improve a light extraction efficiency, the organicEL display device preferably has a resonator structure. Specifically,light emitted from the light emitting layer is caused to resonatebetween a first interface constituted by an interface between the lightreflecting layer disposed below the first electrode and the interlayerinsulation layer located above the light reflecting layer and a secondinterface constituted by an interface between the second electrode andthe organic layer, and a part of the light is emitted from the secondelectrode. In addition, if a distance from a maximum emission positionof the light emitting layer to the first interface is represented by L₁,an optical distance thereof is represented by OL₁, a distance from themaximum emission position of the light emitting layer to the secondinterface is represented by L₂, an optical distance thereof isrepresented by OL₂, and m₁ and m₂ each represent an integer, thefollowing formulas (1-1), (1-2), (1-3), and (1-4) are satisfied.

0.7{−Φ₁/(2π)+m ₁}≤2×OL ₁/λ≤1.2{−Φ₁/(2π)+m ₁}  (1-1)

0.7{−Φ₂/(2π)+m ₂}≤2×OL ₂/λ≤1.2{−Φ₂/(2π)+m ₂}  (1-2)

L₁<L₂   (1-3)

m₁<m₂   (1-4)

Herein,

λ: Maximum peak wavelength of spectrum of light generated in lightemitting layer (or desired wavelength among wavelengths of lightgenerated in light emitting layer)

Φ₁: Phase shift amount (unit: radian) of light reflected on firstinterface

Provided that −2π<Φ₁≤0 is satisfied.

Φ₂: Phase shift amount (unit: radian) of light reflected on secondinterface

Provided that −2π<Φ₂≤0 is satisfied.

Herein, m₁=0 and m₂=1 that can maximize a light extraction efficiencycan be satisfied.

Note that the distance L₁ from the maximum emission position of thelight emitting layer to the first interface means an actual distance(physical distance) from the maximum emission position of the lightemitting layer to the first interface and the distance L₂ from themaximum emission position of the light emitting layer to the secondinterface means an actual distance (physical distance) from the maximumemission position of the light emitting layer to the second interface.In addition, the optical distance is also called an optical path length,and generally means n×L when a light ray passes through a medium havinga refractive index n for a distance L. The same applies to the followingdescription. Therefore, if an average refractive index is represented byn_(ave), the following relations are satisfied.

OL ₁ =L ₁ ×n _(ave)

OL ₂ =L ₂ ×n _(ave)

Here, the average refractive index n_(ave) is obtained by summing up aproduct of the refractive index and the thickness of each layerconstituting the organic layer and the interlayer insulation layer, anddividing the resulting sum by the thickness of the organic layer and theinterlayer insulation layer.

The light reflecting layer and the second electrode absorb a part ofincident light and reflect the rest. Therefore, a phase shift occurs inthe reflected light.

The phase shift amounts Φ₁ and Φ₂ can be determined by measuring valuesof a real number part and an imaginary number part of a complexrefractive index of each of materials constituting the light reflectinglayer and the second electrode, for example, using an ellipsometer, andperforming calculation based on these values (refer to, for example,“Principles of Optic”, Max Born and Emil Wolf, 1974 (PERGAMON PRESS)).Note that the refractive index of the organic layer, the interlayerinsulation layer, or the like can also be determined by measurement withan ellipsometer.

As described above, in an organic EL display device having a resonatorstructure, actually, a red light emitting element constituted byinclusion of a red color filter in a white light emitting element causesred light emitted from the light emitting layer to resonate, and emitsreddish light (light having a light spectrum peak in a red region) fromthe second electrode. Furthermore, the green light emitting elementconstituted by inclusion of a green color filter in a white lightemitting element causes green light emitted from the light emittinglayer to resonate, and emits greenish light (light having a lightspectrum peak in a green region) from the second electrode. Furthermore,the blue light emitting element constituted by inclusion of a blue colorfilter in a white light emitting element causes blue light emitted fromthe light emitting layer to resonate, and emits blueish light (lighthaving a light spectrum peak in a blue region) from the secondelectrode. That is, it is only required to design each of the lightemitting elements by determining a desired wavelength A (specifically,wavelengths of red light, green light, and blue light) among wavelengthsof light generated in the light emitting layer and determining variousparameters such as OL₁ and OL₂ in each of the red light emittingelement, the green light emitting element, and the blue light emittingelement on the basis of formulas (1-2), (1-2), (1-3), and (1-4). Forexample, paragraph

of Japanese Patent Application Laid-Open No. 2012-216495 discloses anorganic EL element having a resonator structure, using a light emittinglayer (organic layer) as a resonance part, and describes that the filmthickness of the organic layer is preferably 80 nm or more and 500 nm orless, and more preferably 150 nm or more and 350 nm or less because adistance from a light emitting point to a reflection surface can beappropriately adjusted.

In an organic EL display device, the thickness of a hole transport layer(hole supply layer) and the thickness of an electron transport layer(electron supply layer) are desirably substantially equal to each other.Alternatively, the thickness of the electron transport layer (electronsupply layer) may be larger than that of the hole transport layer (holesupply layer). As a result, an electron can be supplied sufficiently tothe light emitting layer in an amount necessary for a high efficiency ata low driving voltage. That is, by disposing a hole transport layerbetween the first electrode corresponding to an anode electrode and thelight emitting layer, and forming the hole transport layer with a filmhaving a film thickness smaller than the electron transport layer,supply of holes can be increased. In addition, this makes it possible toobtain a carrier balance with no excess or deficiency of holes andelectrons and a sufficiently large carrier supply amount. Therefore, ahigh emission efficiency can be obtained. In addition, due to no excessor deficiency of holes and electrons, the carrier balance hardlycollapses, drive deterioration is suppressed, and an emission lifetimecan be prolonged.

The display device can be used, for example, as a monitor deviceconstituting a personal computer, or a monitor device incorporated in atelevision receiver, a mobile phone, a personal digital assistant (PDA),or a game machine. Alternatively, the display device or the like of thepresent disclosure can be applied to an electronic view finder (EVF) ora head mounted display (HMD). Alternatively, the display device or thelike of the present disclosure can constitute electronic paper such asan electronic book or electronic newspaper, a bulletin board such as asignboard, a poster, or a blackboard, rewritable paper substituted forprinter paper, a display unit of a home appliance, a card display unitof a point card or the like, an electronic advertisement, or an imagedisplay device in an electronic POP. The display device of the presentdisclosure can be used as a light emitting device, and can constitutevarious lighting devices including a backlight device for a liquidcrystal display device and a planar light source device. The headmounted display includes, for example, (a) a frame attached to the headof an observer and (b) an image display device attached to the frame.The image display device includes (A) the display device of the presentdisclosure and (B) an optical device on which light emitted from thedisplay device of the present disclosure is incident and from which thelight is emitted. The optical device includes (B-1) a light guide platein which the light incident on the light guide plate from the displaydevice of the present disclosure is propagated by total reflection andthen from which the light is emitted toward an observer, (B-2) a firstdeflecting means (for example, including a volume hologram diffractiongrating film) that deflects the light incident on the light guide platesuch that the light incident on the light guide plate is totallyreflected in the light guide plate, and (B-3) a second deflecting means(for example, including a volume hologram diffraction grating film) thatdeflects the light propagated in the light guide plate by totalreflection a plurality of times in order to emit the light propagated inthe light guide plate by total reflection from the light guide plate.

EXAMPLE 1

Example 1 relates to the display device of the present disclosure and amethod for manufacturing the display device. FIG. 1 illustrates aschematic partial cross-sectional view of the display device of thepresent disclosure. The display device of Example 1 is specificallyconstituted by an organic EL display device. The light emitting elementof Example 1 is specifically constituted by an organic EL element.

The display device of Example 1 or a display device in the method formanufacturing the display device of Example 1

includes a plurality of pixels each including a first light emittingelement 10R, a second light emitting element 10G, and a third lightemitting element 10B, arranged in a two-dimensional matrix.

Each of the pixels includes a lowermost layer/interlayer insulationlayer 30, a first interlayer insulation layer 31 formed on the lowermostlayer/interlayer insulation layer 30, a second interlayer insulationlayer 32 formed on the first interlayer insulation layer 31, and anuppermost layer/interlayer insulation layer 33.

Each of the light emitting elements 10R, 10G, and 10B includes:

a first electrode 51 formed on the uppermost layer/interlayer insulationlayer 33;

an insulation film 60 formed at least on a region of the uppermostlayer/interlayer insulation layer 33 where the first electrode 51 is notformed;

an organic layer 53 formed over the insulation film 60 from above thefirst electrode 51 and including a light emitting layer containing anorganic light emitting material; and

a second electrode 52 formed on the organic layer 53.

The first light emitting element 10R includes a first light reflectinglayer 36R formed on the lowermost layer/interlayer insulation layer 30.

The second light emitting element 10G includes a second light reflectinglayer 36G formed on the first interlayer insulation layer 31.

The third light emitting element 10B includes a third light reflectinglayer 36B formed on the second interlayer insulation layer 32.

In addition, in the display device of Example 1,

the uppermost layer/interlayer insulation layer 33 covers the lowermostlayer/interlayer insulation layer 30, the first light reflecting layer36R, the second light reflecting layer 36G, and the third lightreflecting layer 36B,

a first groove 42 ₁ is formed in a portion of the uppermostlayer/interlayer insulation layer 33 located in a boundary regionbetween the first light emitting element 10R and the second lightemitting element 10G,

a second groove 42 ₂ is formed in a portion of the uppermostlayer/interlayer insulation layer 33 located in a boundary regionbetween the second light emitting element 10G and the third lightemitting element 10B, and

a third groove 42 ₃ is formed in a portion of the uppermostlayer/interlayer insulation layer 33 located in a boundary regionbetween the first light emitting element 10R and the third lightemitting element 10B. In addition, a light shielding layer 44 is formedinside the first groove 42 ₁, the second groove 42 ₂, and the thirdgroove 42 ₃,

a lowermost portion of a bottom 43 ₁ of the first groove 42 ₁ and alowermost portion of a bottom 43 ₃ of the third groove 42 ₃ are locatedat a position higher than a top surface of the first light reflectinglayer 36R, and

a lowermost portion of a bottom 43 ₂ of the second groove 42 ₂ islocated at a position higher than a top surface of the second lightreflecting layer 36G.

In other words, the lowermost portion of the bottom 43 ₁ of the firstgroove 42 ₁ and the lowermost portion of the bottom 43 ₃ of the thirdgroove 42 ₃ are located on a side closer to a top surface of theuppermost layer/interlayer insulation layer 33 than a top surface of thefirst light reflecting layer 36R, and the lowermost portion of thebottom 43 ₂ of the second groove 42 ₂ is located on a side closer to atop surface of the uppermost layer/interlayer insulation layer 33 than atop surface of the second light reflecting layer 36G. Note that thelowermost portion of the bottom 43 ₁ of the first groove 42 ₁, thelowermost portion of the bottom 43 ₂ of the second groove 42 ₂, and thelowermost portion of the bottom 43 ₃ of the third groove 42 ₃ refer tothe closest portion to the lowermost layer/interlayer insulation layer30.

In addition, the lowermost portion of the bottom 43 ₁ of the firstgroove 42 ₁ and the lowermost portion of the bottom 43 ₃ of the thirdgroove 42 ₃ are located at a position closer to the first light emittingelement 10R than the third light emitting element 10B, and the lowermostportion of the bottom 43 ₂ of the second groove 42 ₂ is located at aposition closer to the second light emitting element 10G than the thirdlight emitting element 10B.

Note that the first interlayer insulation layer 31, the secondinterlayer insulation layer 32, and the uppermost layer/interlayerinsulation layer 33 are collectively referred to as an interlayerinsulation layer/laminated structure 34. The lowermost layer/interlayerinsulation layer 30, the interlayer insulation layer/laminated structure34, the organic layer 53, and the second electrode 52 are common in theplurality of light emitting elements. The insulation film 60 extends toa top surface of an edge of the first electrode 51.

In another expression, the display device of Example 1 includes a firstsubstrate 11, a second substrate 12, and an image display unit 13sandwiched by the first substrate 11 and the second substrate 12. In theimage display unit 13, the plurality of light emitting elements 10R,10G, and 10B of Example 1 is arranged in a two-dimensional matrix. Here,the light emitting elements are formed on a side of the first substrate11. In addition, the display device of Example 1 is a top emission typedisplay device that emits light from the second substrate 12. In the topemission type display device, color filters CF_(R), CF_(G), and CF_(B),and a black matrix layer BM are formed on a surface side of the secondsubstrate 12 opposed to the first substrate 11. One sub-pixel isconstituted by one light emitting element.

One pixel is constituted by three light emitting elements of the redlight emitting element 10R, the green light emitting element 10G, andthe blue light emitting element 10B. The second substrate 12 includesthe color filters CF_(R), CF_(G), and CF_(B). The organic EL elementemits white light, and the light emitting elements 10R, 10G, and 10B areconstituted by a combination of a white light emitting element thatemits white light and the color filters CF_(R), CF_(G), and CF_(B),respectively. That is, the light emitting layer emits white light as awhole. In addition, a black matrix layer BM is disposed between a colorfilter and a color filter. The number of pixels is, for example,1920×1080. One light emitting element (display element) constitutes onesub-pixel, and the number of light emitting elements (specifically,organic EL elements) is three times the number of pixels.

The first electrode 51 functions as an anode electrode, and the secondelectrode 52 functions as a cathode electrode. The first electrode 51 ismade by including a transparent conductive material such as ITO having athickness of 0.01 μm to 0.1 μm, and the second electrode 52 is made byincluding a Mg—Ag alloy having a thickness of 4 nm to 20 nm. The firstelectrode 51 is formed on the basis of a combination of a vacuum vapordeposition method and an etching method. Furthermore, a film of thesecond electrode 52 is formed by a film formation method in which energyof film formation particles is small, such as a vacuum vapor depositionmethod, and is not patterned. The organic layer 53 is not patterned,either. The first light reflecting layer 36R, the second lightreflecting layer 36G, and the third light reflecting layer 36B have alaminated structure of aluminum (Al)-copper (Cu)/titanium (Ti).Furthermore, the first substrate 11 includes a silicon semiconductorsubstrate, and the second substrate 12 includes a glass substrate.

In addition, the light shielding layer 44 includes tungsten (W), thelowermost layer/interlayer insulation layer 30 includes SiO₂, the firstinterlayer insulation layer 31 includes SiN, the second interlayerinsulation layer 32 includes SiO₂, the uppermost layer/interlayerinsulation layer 33 includes SiO₂, and the insulation film 60 includesSiON. However, materials constituting these layers are not limited tothese materials.

In Example 1, the organic layer 53 has a laminated structure of a holeinjection layer (HIL), a hole transport layer (HTL), a light emittinglayer, an electron transport layer (ETL), and an electron injectionlayer (EIL). The light emitting layer is constituted by at least twolight emitting layers that emit different colors, and light emitted fromthe organic layer 53 is white. Specifically, the light emitting layerhas a structure in which three layers of a red light emitting layer thatemits red light, a green light emitting layer that emits green light,and a blue light emitting layer that emits blue light are laminated. Thelight emitting layer may have a structure in which two layers of a bluelight emitting layer that emits blue light and a yellow light emittinglayer that emits yellow light are laminated or a structure in which twolayers of a blue light emitting layer that emits blue light and anorange light emitting layer that emits orange light are laminated. Thered light emitting element 10R to display a red color includes the redcolor filter CF_(R). The green light emitting element 10G to display agreen color includes the green color filter CF_(G). The blue lightemitting element 10B to display a blue color includes the blue colorfilter CF_(B). The red light emitting element 10R, the green lightemitting element 10G, and the blue light emitting element 10B have thesame configuration and structure except for the color filters andpositions of the light reflecting layer. The black matrix layer BM isformed between a color filter CF and a color filter CF. In addition, thecolor filter CF and the black matrix layer BM are formed on a surfaceside of the second substrate 12 opposed to the first substrate 11. Thismakes it possible to shorten a distance between the light emitting layerand the color filter CF and to suppress color mixing caused by incidenceof light emitted from the light emitting layer on an adjacent colorfilter CF of another color.

The hole injection layer increases a hole injection efficiency,functions as a buffer layer for preventing leakage, and has a thicknessof about 2 nm to 10 nm, for example. The hole injection layer includes ahexaazatriphenylene derivative represented by the following formula (A)or (B), for example.

Herein, R¹ to R⁶ each independently represent a substituent selectedfrom a hydrogen atom, a halogen atom, a hydroxy group, an amino group,an arulamino group, a substituted or unsubstituted carbonyl group having20 or less carbon atoms, a substituted or unsubstituted carbonyl estergroup having 20 or less carbon atoms, a substituted or unsubstitutedalkyl group having 20 or less carbon atoms, a substituted orunsubstituted alkenyl group having 20 or less carbon atoms, asubstituted or unsubstituted alkoxy group having 20 or less carbonatoms, a substituted or unsubstituted aryl group having 30 or lesscarbon atoms, a substituted or unsubstituted heterocyclic group having30 or less carbon atoms, a nitrile group, a cyano group, a nitro group,and a silyl group, and adjacent R^(m)s (m=1 to 6) may be bonded to eachother via a cyclic structure. In addition, X¹ to X⁶ each independentlyrepresent a carbon atom or a nitrogen atom.

The hole transport layer is a layer that increases a hole transportefficiency to the light emitting layer. When an electric field isapplied to the light emitting layer, recombination of electrons andholes occurs to generate light. The electron transport layer is a layerthat increases an electron transport efficiency to the light emittinglayer, and the electron injection layer is a layer that increases anelectron injection efficiency to the light emitting layer.

The hole transport layer includes4,4′,4″-tris(3-methylphenylphenylamino) triphenylamine <m-MTDATA> orα-naphthylphenyl diamine <αNPD> having a thickness of about 40 nm, forexample.

The light emitting layer is a light emitting layer that generates whitelight by color mixing, and is formed by laminating a red light emittinglayer, a green light emitting layer, and a blue light emitting layer asdescribed above, for example.

When an electric field is applied to the red light emitting layer, apart of holes injected from the first electrode 51 and a part ofelectrons injected from the second electrode 52 are recombined togenerate red light. Such a red light emitting layer contains at leastone kind of material among a red light emitting material, a holetransport material, an electron transport material, and a both chargetransport material, for example. The red light emitting material may bea fluorescent material or a phosphorescent material. The red lightemitting layer having a thickness of about 5 nm is formed by mixing 30%by mass of 2,6-bis[(4′-methoxydiphenylamino)styryl]-1,5-dicyanonaphthalene <BSN> with 4,4-bis(2,2-diphenylvinyl)biphenyl <DPVBi>, for example.

In the green light emitting layer, by application of an electric field,a part of holes injected from the first electrode 51 and a part ofelectrons injected from the second electrode 52 are recombined togenerate green light. Such a green light emitting layer contains atleast one kind of material among a green light emitting material, a holetransport material, an electron transport material, and a both chargetransport material, for example. The green light emitting material maybe a fluorescent material or a phosphorescent material. The green lightemitting layer having a thickness of about 10 nm is formed by mixing 5%by mass of coumarin 6 with DPVBi, for example.

In the blue light emitting layer, by application of an electric field, apart of holes injected from the first electrode 51 and a part ofelectrons injected from the second electrode 52 are recombined togenerate blue light. Such a blue light emitting layer contains at leastone kind of material among a blue light emitting material, a holetransport material, an electron transport material, and a both chargetransport material, for example. The blue light emitting material may bea fluorescent material or a phosphorescent material. The blue lightemitting layer having a thickness of about 30 nm is formed by mixing2.5% by mass of 4,4′-bis[2-{4-(N,N-diphenylamino) phenyl} vinyl]biphenyl <DPAVBi> with DPVBi, for example.

The electron transport layer having a thickness of about 20 nm includes8-hydroxyquinoline aluminum <Alq3>, for example. The electron injectionlayer having a thickness of about 0.3 nm includes LiF, Li₂O, or thelike, for example.

An insulating or conductive protection film 14 (specifically, includingSiN, ITO, IGZO, or IZO, for example) is disposed above the secondelectrode 52 in order to prevent moisture from reaching the organiclayer 53. Furthermore, the protective film 14 and the second substrate12 are bonded to each other via a resin layer (sealing resin layer) 15including an epoxy-based adhesive, for example.

In addition, the lowermost layer/interlayer insulation layer 30, theinterlayer insulation layer/laminated structure 34, the organic layer53, and the second electrode 52 are common in the plurality of lightemitting elements. That is, the lowermost layer/interlayer insulationlayer 30, the interlayer insulation layer/laminated structure 34, theorganic layer 53, and the second electrode 52 are not patterned and arein a so-called solid film state. As described above, by forming a solidfilm of a light emitting layer common in all the light emitting elementswithout forming the light emitting layer separately for each lightemitting element (patterning formation), the light emitting elements canbe also applied to a small and high-resolution display device having afield angle of several inches or less and a pixel pitch of several tensof micrometers or less, for example.

A light emitting element has a resonator structure using the organiclayer 53 as a resonance part. Incidentally, in order to appropriatelyadjust a distance from a light emitting surface to a reflecting surface(specifically, a distance from a light emitting surface to the lightreflecting layer 36R, 36G, or 36B and the second electrode 52), thethickness of the organic layer 53 is preferably 8×10⁻⁸ m or more and5×10⁻⁷ m or less, and more preferably 1.5×10⁻⁷ m or more and 3.5×10⁻⁷ mor less. In an organic EL display device having a resonator structure,actually, the red light emitting element 10R causes red light emittedfrom the light emitting layer to resonate, and emits reddish light(light having a light spectrum peak in a red region) from the secondelectrode 52. In addition, the green light emitting element 10G causesgreen light emitted from the light emitting layer to resonate, and emitsgreenish light (light having a light spectrum peak in a green region)from the second electrode 52. Furthermore, the blue light emittingelement 10B causes blue light emitted from the light emitting layer toresonate, and emits bluish light (light having a light spectrum peak ina blue region) from the second electrode 52.

In Example 1, a transistor (specifically, for example, MOSFET) 20 formedon a silicon semiconductor substrate (first substrate 11) is disposedunder the lowermost layer/interlayer insulation layer 30. In addition,the first electrode 51 is connected to the transistor 20 formed on thesilicon semiconductor substrate (first substrate 11) via a contact hole(contact plug) formed in the lowermost layer/interlayer insulation layer30 and the interlayer insulation layer/laminated structure 34. Note thatthe contact hole is not illustrated. Here, the transistor 20 including aMOSFET is constituted by a gate electrode 21, a gate insulation layer22, a channel formation region 23, and a source/drain region 24. Anelement isolation region 25 is formed between the transistors 20, andthe transistors 20 are thereby separated from each other.

Hereinafter, the method for manufacturing the display device of Example1 will be described with reference to FIGS. 2A, 2B, 2C, 3A, 3B, 4A, 4B,5A, 5B, and 6 which are schematic partial end views of the lowermostlayer/interlayer insulation layer and the like.

[Step-100]

First, a light emitting element driving unit is formed on a siliconsemiconductor substrate (first substrate 11) on the basis of a knownMOSFET manufacturing process.

[Step-110]

Subsequently, the lowermost layer/interlayer insulation layer 30, thepatterned first interlayer insulation layer 31, and the patterned secondinterlayer insulation layer 32 are formed. Specifically, the lowermostlayer/interlayer insulation layer 30 is formed on the entire surface onthe basis of a CVD method. Thereafter, the first interlayer insulationlayer 31 and the second interlayer insulation layer 32 are sequentiallyformed on the lowermost layer/interlayer insulation layer 30 on thebasis of the CVD method. Then, the second interlayer insulation layer 32is patterned, and the first interlayer insulation layer 31 is furtherpatterned on the basis of a known RIE method. In this way, the structureillustrated in FIG. 2A can be obtained.

[Step-120]

Thereafter, a light reflecting layer 35 is formed on the entire surfaceon the basis of a sputtering method (refer to FIG. 2B), and then aresist layer 37 is formed on the basis of a photolithography technique.In this way, the structure illustrated in FIG. 2C can be obtained.

Then, the light reflecting layer 35 is patterned on the basis of a knownRIE method. In this way, the first light reflecting layer 36R can beformed on a region of the lowermost layer/interlayer insulation layer 30where the first light emitting element 10R is to be formed, the secondlight reflecting layer 36G can be formed on a region of the firstinterlayer insulation layer 31 where the second light emitting element10G is to be formed, and the third light reflecting layer 36B can beformed on a region of the second interlayer insulation layer 32 wherethe third light emitting element 10B is to be formed (refer to FIG. 3A).

[Step-130]

Thereafter, at least a portion of the first interlayer insulation layer31 located in a boundary region between the first light emitting element10R and the second light emitting element 10G (in Example 1,specifically, a portion of the lowermost layer/interlayer insulationlayer 30 and a portion of the first interlayer insulation layer 31located in a boundary region between the first light emitting element10R and the second light emitting element 10G) is etched to form a firstrecess 41 ₁. At the same time, at least a portion of the secondinterlayer insulation layer 32 located in a boundary region between thesecond light emitting element 10G and the third light emitting element10B (in Example 1, specifically, a portion of the first interlayerinsulation layer 31 and a portion of the second interlayer insulationlayer 32 located in a boundary region between the second light emittingelement 10G and the third light emitting element 10B) is etched to forma second recess 41 ₂. At the same time, at least a portion of the firstinterlayer insulation layer 31 and a portion of the second interlayerinsulation layer 32 located in a boundary region between the first lightemitting element 10R and the third light emitting element 10B (inExample 1, specifically, a portion of the lowermost layer/interlayerinsulation layer 30, a portion of the first interlayer insulation layer31, and a portion of the second interlayer insulation layer 32 locatedin a boundary region between the first light emitting element 10R andthe third light emitting element 10B) is etched to form a third recess41 ₃. For the above steps, refer to FIGS. 3B and 4A. Then, the resistlayer 37 is removed. In this way, the structure illustrated in FIG. 4Bcan be obtained.

[Step-140]

Next, the uppermost layer/interlayer insulation layer 33 is formed onthe entire surface on the basis of a plasma CVD method (refer to FIG.5A). Thereafter, the uppermost layer/interlayer insulation layer 33 isflattened on the basis of a CMP method. In this way, as illustrated inFIG. 5B, the first groove 42 ₁, the second groove 42 ₂, and the thirdgroove 42 ₃ are formed in a portion of the uppermost layer/interlayerinsulation layer 33 above the first recess 41 ₁, the second recess 41 ₂,and the third recess 41 ₃, respectively. These grooves 42 ₁, 42 ₂, and42 ₃ are formed by a self-alignment method.

[Step-150]

Thereafter, the light shielding layer 44 is formed inside the firstgroove 42 ₁, the second groove 42 ₂, and the third groove 42 ₃.Specifically, a tungsten layer is formed on the entire surface on thebasis of a tungsten CVD method, and the tungsten layer on the uppermostlayer/interlayer insulation layer 33 is removed on the basis of a CMPmethod. In this way, the structure illustrated in FIG. 6 can beobtained.

A lowermost portion of the bottom 43 ₁ of the first groove 42 ₁ and alowermost portion of the bottom 43 ₃ of the third groove 42 ₃ arelocated at a position higher than a top surface of the first lightreflecting layer 36R, and a lowermost portion of the bottom 43 ₃ of thesecond groove 42 ₂ is located at a position higher than a top surface ofthe second light reflecting layer 36G. In addition, a lowermost portionof the bottom 43 ₁ of the first groove 42 ₁ and the lowermost portion ofthe bottom 43 ₃ of the third groove 42 ₃ are located at a positioncloser to the first light emitting element 10R than the third lightemitting element 10B, and a lowermost portion of the bottom 43 ₂ of thesecond groove 42 ₂ is located at a position closer to the second lightemitting element 10G than the third light emitting element 10B.

[Step-160]

Then, a connection hole is formed in a portion of the lowermostlayer/interlayer insulation layer 30 and the interlayer insulationlayer/laminated structure 34 located above one of source/drain regionsof the transistor 20 on the basis of a photolithography technique and anetching technique. Thereafter, a metal layer is formed on the uppermostlayer/interlayer insulation layer 33 including the connection hole onthe basis of a sputtering method, for example. Subsequently, the metallayer is patterned on the basis of a photolithography technique and anetching technique, and the first electrode 51 can be thereby formed onthe uppermost layer/interlayer insulation layer 33. The first electrode51 is separated for each of the light emitting elements. At the sametime, a contact hole (contact plug) (not illustrated) for electricallyconnecting the first electrode 51 to the transistor 20 can be formed inthe connection hole. Note that the contact hole may be formedsimultaneously with forming the light shielding layer 44 inside thefirst groove 42 ₁, the second groove 42 ₂, and the third groove 42 ₃.

[Step-170]

Subsequently, the insulation film 60 is formed on the entire surface,for example, on the basis of a CVD method. Thereafter, an opening 61 isformed in a part of the insulation film 60 on the first electrode 51 onthe basis of a photolithography technique and an etching technique. Thefirst electrode 51 is exposed to a bottom of the opening 61.

[Step-180]

Thereafter, a film of the organic layer 53 is formed on the firstelectrode 51 and the insulation film 60 by a PVD method such as a vacuumvapor deposition method or a sputtering method, or a coating method suchas a spin coating method or a die coating method, for example.Subsequently, the second electrode 52 is formed on the entire surface ofthe organic layer 53 on the basis of a vacuum vapor deposition method orthe like, for example. In this way, films of the organic layer 53 andthe second electrode 52 can be continuously formed on the firstelectrode 51, for example, in a vacuum atmosphere. Thereafter, theprotective film 14 is formed on the entire surface by a CVD method or aPVD method, for example. Finally, the protective film 14 and the secondsubstrate 12 are bonded to each other via the resin layer (sealing resinlayer) 15. Note that the color filters CF_(R), CF_(G), and CF_(B), andthe black matrix layer BM are formed in advance on the second substrate12. Then, a surface on which the color filter CF is formed is used as abonding surface. In this way, the organic EL display device illustratedin FIG. 1 can be obtained.

As described above, in the method for manufacturing the display deviceof Example 1, in [step-150], the light shielding layer 44 is formedinside the first groove 42 ₁, the second groove 42 ₂, and the thirdgroove 42 ₃. In addition, in the display device of Example 1, the lightshielding layer 44 is formed inside the first groove 42 ₁, the secondgroove 42 ₂, and the third groove 42 ₃. Therefore, it is possible tomanufacture a display device hardly causing entry of light into anadjacent light emitting element. That is, it is possible to reduce aratio at which light emitted from a certain light emitting elemententers an adjacent light emitting element, and to suppress occurrence ofa phenomenon that color mixing occurs and chromaticity of the entirepixels is shifted from desired chromaticity. In addition, color mixingcan be prevented. Therefore, color purity increases when monochromaticlight is emitted from a pixel, and a chromaticity point is deep.Therefore, a color gamut is widened, and a range of color expression ofthe display device is widened. In addition, a color filter is disposedfor each pixel in order to increase color purity. This makes it possibleto reduce the film thickness of the color filter or to omit the colorfilter, and makes it possible to extract light absorbed by the colorfilter. As a result, this leads to improvement of luminous efficiency.

Furthermore, in [step-140], the uppermost layer/interlayer insulationlayer 33 is formed on the entire surface, and then the uppermostlayer/interlayer insulation layer 33 is flattened. The first groove 42₁, the second groove 42 ₂, and the third groove 42 ₃ can be therebyformed by a so-called self-alignment method. Therefore, a light emittingelement can be micronized. Furthermore, a relationship between lowermostportions of the bottoms 43 ₁, 43 ₂, and 43 ₃ of grooves and the heightsof top surfaces of the light reflecting layers 36R, 36G, and 36B isdefined. Therefore, it is possible to reliably prevent contact betweenthe grooves 42 ₁, 42 ₂, and 42 ₃ and the light reflecting layers 36R,36G, and 36B, and to avoid occurrence of a problem such as variation inluminescent color.

EXAMPLE 2

Example 2 is a modification of Example 1. As illustrated in a schematicpartial cross-sectional view in FIG. 7, an insulation film 62 includingSiON, SiO₂, or a polyimide resin is formed on a region of the uppermostlayer/interlayer insulation layer 33 where the first electrode 51 is notformed. The organic layer 53 is formed on the first electrode 51 and theinsulation film 62 which are flat as a whole, and the organic layer 53is also flat. In this way, by forming the organic layer 53 on the firstelectrode 51 and the insulation film 62 which are flat as a whole, it ispossible to prevent occurrence of a problem such as abnormal lightemission at an end of an opening of the insulation film.

In the display device of Example 2, for example, in a similar step to[Step-170] of Example 1, by performing a flattening treatment after theinsulation film 62 is formed on the entire surface, for example, on thebasis of a CVD method, it is only required to leave the insulation film62 on a region of the uppermost layer/interlayer insulation layer 33where the first electrode 51 is not formed. The configurations andstructures of the light emitting element and the display device ofExample 2 can be similar to those of the light emitting element and thedisplay device of Example 1 except for the above points, and thereforedetailed description will be omitted.

EXAMPLE 3

Example 3 is a modification of Example 1.

By the way, a phenomenon that a leakage current flows between the firstelectrode in a certain light emitting element and the second electrodeconstituting an adjacent light emitting element may occur. In addition,when such a phenomenon occurs, light emission occurs in a light emittingelement which should not emit light originally. Meanwhile, intensity ofan electric field in a light emitting element which should emit light isreduced. As a result, blurring may occur in an image, or thechromaticity of the entire pixels may be shifted from desiredchromaticity. In order to solve such a problem, in Example 3, at thetime of film formation of the organic layer 53, at least a part of apart (specifically, for example, hole injection layer) of the organiclayer 53 is made discontinuous at an end of the insulation film 60,specifically, at an edge of the opening 61 disposed in the insulationfilm 60. In this way, for example, by making at least a part of a holeinjection layer discontinuous, the resistance of the hole injectionlayer is increased, and occurrence of a phenomenon that a leakagecurrent flows between the first electrode in a certain light emittingelement and the second electrode constituting an adjacent light emittingelement can be reliably prevented.

In order to make at least a part of the hole injection layerdiscontinuous, it is only required to optimize an inclination state ofan edge of the opening 61 disposed in the insulation film 60, and tooptimize film formation conditions of the hole injection layer.Alternatively, for example, in the display device described in Example1, it is only required to form a second insulation film having an end(eaves-like end) protruding into the opening 61 on the insulation film60, and to make at least a part of the hole injection layerdiscontinuous at a protruding end of the second insulation film.

Alternatively, [step 160] of Example 1 is performed, and then a kind ofsacrificial layer is formed on the entire surface. Subsequently, theinsulation film 60 is formed, and the opening 61 is formed in a part ofthe insulation film 60 in a similar manner to [step-170] of Example 1.The sacrificial layer is exposed to a bottom of the opening 61. Thesacrificial layer formed in a portion of the uppermost layer/interlayerinsulation layer 33 located between the first electrode 51 and the firstelectrode 51 is covered with the insulation film 60. Then, a portion ofthe sacrificial layer exposed to the bottom of the opening 61 isremoved. A gap is generated between the first electrode 51 and theportion of the insulation film 60 located above the first electrode 51due to removal of the sacrificial layer. That is, the portion of theinsulation film 60 located above the first electrode 51 has a kind ofeaves-like shape. Therefore, by forming a hole injection layer in thisstate, at least a part of the hole injection layer can be madediscontinuous.

Hitherto, the present disclosure has been described on the basis of thepreferable Examples. However, the present disclosure is not limited tothese Examples. The configurations and structures of the display device(organic EL display device) and the light emitting element (organic ELelement) described in Examples are illustrative and can be changedappropriately. The method for manufacturing the display device is alsoillustrative and can be changed appropriately. In Examples, one pixel isconstituted exclusively by three sub-pixels using a combination of awhite light emitting element and a color filter. However, for example,one pixel may be constituted by four sub-pixels obtained by adding alight emitting element that emits white light. In Examples, the lightemitting element driving unit is constituted by a MOSFET, but can bealso constituted by a TFT.

In Examples, the lowermost layer/interlayer insulation layer, thepatterned first interlayer insulation layer, and the patterned secondinterlayer insulation layer are formed, then the light reflecting layeris formed on the entire surface, and then the light reflecting layer ispatterned to form the first light reflecting layer, the second lightreflecting layer, and the third light reflecting layer. Subsequently,the first recess, the second recess, and the third recess are formed.That is, steps (A), (B), and (C) in the method for manufacturing adisplay device according to the present disclosure are performed.However, alternatively, for example, the following steps may be adopted.

[Step-A] forming a first light reflecting layer on a region of alowermost layer/interlayer insulation layer where a first light emittingelement is to be formed, then

[Step-B] forming a first interlayer insulation layer on the lowermostlayer/interlayer insulation layer and then forming a second lightreflecting layer on the first interlayer insulation layer, then

[Step-C] forming a second interlayer insulation layer on the firstinterlayer insulation layer and then forming a third light reflectinglayer on the second interlayer insulation layer, and then

[Step-D] removing a desired portion of the second interlayer insulationlayer, the first interlayer insulation layer, and the lowermostlayer/interlayer insulation layer by etching,

forming a first recess at least in a portion of the first interlayerinsulation layer located in a boundary region between a first lightemitting element and a second light emitting element (specifically, forexample, a portion of the lowermost layer/interlayer insulation layerand a portion of the first interlayer insulation layer), at the sametime,

forming a second recess at least in a portion of the second interlayerinsulation layer located in a boundary region between the second lightemitting element and a third light emitting element (specifically, forexample, a portion of the first interlayer insulation layer and aportion of the second interlayer insulation layer), and at the sametime,

forming a third recess at least in a portion of the first interlayerinsulation layer and a portion of the second interlayer insulation layerlocated in a boundary region between the first light emitting elementand the third light emitting element (specifically, for example, aportion of the lowermost layer/interlayer insulation layer, a portion ofthe first interlayer insulation layer, and a portion of the secondinterlayer insulation layer).

Note that the present disclosure may have the following configurations.

[A01] «Method for Manufacturing Display Device»

A method for manufacturing a display device including a plurality ofpixels each including a first light emitting element, a second lightemitting element, and a third light emitting element, arranged in atwo-dimensional matrix,

each of the pixels including a lowermost layer/interlayer insulationlayer, a first interlayer insulation layer formed on the lowermostlayer/interlayer insulation layer, a second interlayer insulation layerformed on the first interlayer insulation layer, and an uppermostlayer/interlayer insulation layer,

each of the light emitting elements including:

a first electrode formed on the uppermost layer/interlayer insulationlayer;

an insulation film formed at least on a region of the uppermostlayer/interlayer insulation layer where the first electrode is notformed;

an organic layer formed over the insulation film from above the firstelectrode and including a light emitting layer containing an organiclight emitting material; and

a second electrode formed on the organic layer,

the first light emitting element including a first light reflectinglayer formed on the lowermost layer/interlayer insulation layer,

the second light emitting element including a second light reflectinglayer formed on the first interlayer insulation layer, and

the third light emitting element including a third light reflectinglayer formed on the second interlayer insulation layer, the methodincluding:

(A) forming a lowermost layer/interlayer insulation layer, a patternedfirst interlayer insulation layer, and a patterned second interlayerinsulation layer; then

(B) forming a light reflecting layer on the entire surface and thenpatterning the light reflecting layer to form a first light reflectinglayer on a region of the lowermost layer/interlayer insulation layerwhere a first light emitting element is to be formed, to form a secondlight reflecting layer on a region of the first interlayer insulationlayer where a second light emitting element is to be formed, and to forma third light reflecting layer on a region of the second interlayerinsulation layer where a third light emitting element is to be formed;then

(C) etching at least a portion of the first interlayer insulation layerlocated in a boundary region between the first light emitting elementand the second light emitting element to form a first recess, at thesame time

etching at least a portion of the second interlayer insulation layerlocated in a boundary region between the second light emitting elementand the third light emitting element to form a second recess, and at thesame time

etching at least a portion of the first interlayer insulation layer anda portion of the second interlayer insulation layer located in aboundary region between the first light emitting element and the thirdlight emitting element to form a third recess; then

(D) forming an uppermost layer/interlayer insulation layer on the entiresurface and then flattening the uppermost layer/interlayer insulationlayer to form a first groove, a second groove, and a third groove in aportion of the uppermost layer/interlayer insulation layer above thefirst recess, the second recess, and the third recess, respectively; andthen

(E) forming a light shielding layer inside the first groove, the secondgroove, and the third groove.

[A02] The method for manufacturing a display device according to [A01],in which, in step (C),

a portion of the lowermost layer/interlayer insulation layer and aportion of the first interlayer insulation layer located in a boundaryregion between the first light emitting element and the second lightemitting element are etched to form a first recess, at the same time

a portion of the first interlayer insulation layer and a portion of thesecond interlayer insulation layer located in a boundary region betweenthe second light emitting element and the third light emitting elementare etched to form a second recess, and at the same time

a portion of the lowermost layer/interlayer insulation layer, a portionof the first interlayer insulation layer, and a portion of the secondinterlayer insulation layer located in a boundary region between thefirst light emitting element and the third light emitting element areetched to form a third recess.

[A03] The method for manufacturing a display device according to [A01]or [A02], in which

a lowermost portion of a bottom of the first groove and a lowermostportion of a bottom of the third groove are located at a position higherthan a top surface of the first light reflecting layer, and

a lowermost portion of a bottom of the second groove is located at aposition higher than a top surface of the second light reflecting layer.

[A04] The method for manufacturing a display device according to any oneof [A01] to [A03], in which

the lowermost portion of the bottom of the first groove and thelowermost portion of the bottom of the third groove are located at aposition closer to the first light emitting element than the third lightemitting element, and

the lowermost portion of the bottom of the second groove is located at aposition closer to the second light emitting element than the thirdlight emitting element.

[B01] «Display device»

A display device including a plurality of pixels each including a firstlight emitting element, a second light emitting element, and a thirdlight emitting element, arranged in a two-dimensional matrix, in which

each of the pixels includes a lowermost layer/interlayer insulationlayer, a first interlayer insulation layer formed on the lowermostlayer/interlayer insulation layer, a second interlayer insulation layerformed on the first interlayer insulation layer, and an uppermostlayer/interlayer insulation layer,

each of the light emitting elements includes:

a first electrode formed on the uppermost layer/interlayer insulationlayer;

an insulation film formed at least on a region of the uppermostlayer/interlayer insulation layer where the first electrode is notformed;

an organic layer formed over the insulation film from above the firstelectrode and including a light emitting layer containing an organiclight emitting material; and

a second electrode formed on the organic layer,

the first light emitting element includes a first light reflecting layerformed on the lowermost layer/interlayer insulation layer,

the second light emitting element includes a second light reflectinglayer formed on the first interlayer insulation layer,

the third light emitting element includes a third light reflecting layerformed on the second interlayer insulation layer,

the uppermost layer/interlayer insulation layer covers the lowermostlayer/interlayer insulation layer, the first light reflecting layer, thesecond light reflecting layer, and the third light reflecting layer,

a first groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the first lightemitting element and the second light emitting element,

a second groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the second lightemitting element and the third light emitting element,

a third groove is formed in a portion of the uppermost layer/interlayerinsulation layer located in a boundary region between the first lightemitting element and the third light emitting element,

a light shielding layer is formed inside the first groove, the secondgroove, and the third groove,

a lowermost portion of a bottom of the first groove and a lowermostportion of a bottom of the third groove are located at a position higherthan a top surface of the first light reflecting layer, and

a lowermost portion of a bottom of the second groove is located at aposition higher than a top surface of the second light reflecting layer.

[B02] The display device according to [B01], in which

the lowermost portion of the bottom of the first groove and thelowermost portion of the bottom of the third groove are located at aposition closer to the first light emitting element than the third lightemitting element, and

the lowermost portion of the bottom of the second groove is located at aposition closer to the second light emitting element than the thirdlight emitting element.

REFERENCE SIGNS LIST

-   10R First light emitting element (red light emitting element)-   10G Second light emitting element (green light emitting element)-   10B Third light emitting element (blue light emitting element)-   11 First substrate-   12 Second substrate-   13 Image display unit-   14 Protective film-   15 Resin layer (sealing resin layer)-   CF, CF_(R), CF_(G), CF_(B) Color filter-   BM Black matrix layer-   20 Transistor-   21 Gate electrode-   22 Gate insulation layer-   23 Channel formation region-   24 Source/drain region-   25 Element isolation region-   30 Lowermost layer/interlayer insulation layer-   31 First interlayer insulation layer-   32 Second interlayer insulation layer-   33 Uppermost layer/interlayer insulation layer-   34 Interlayer insulation layer/laminated structure-   35 Light reflecting layer-   36R First light reflecting layer-   36G Second light reflecting layer-   36B Third light reflecting layer-   37 Resist layer-   41 ₁, 41 ₂, 41 ₃ Recess-   42 ₁, 42 ₂, 42 ₃ Groove-   43 ₁, 43 ₂, 43 ₃ Bottom of groove-   44 Light shielding layer-   51 First electrode-   52 Second electrode-   53 Organic layer-   60, 62 Insulation film-   61 Opening

1. A display device comprising: a substrate; a plurality of transistorsarranged on the substrate; an insulation layer disposed over theplurality of transistors a plurality of light emitting elementsincluding a first light emitting element, a second light emittingelement, and a third light emitting element, the plurality of lightemitting elements being arranged on the insulation layer, the pluralityof light emitting elements being arranged in a two-dimensional matrix; acolor filter comprising a red region corresponding to the first lightemitting element, a green region corresponding to the second lightemitting element, and a blue region corresponding to the third lightemitting element, the color filter being disposed at a light emissionside of the plurality of light emitting elements; a first lightshielding layer disposed between the first light emitting element andthe second light emitting element; and a second light shielding layerdisposed between the second light emitting element and the third lightemitting element, wherein each of the first, second, and third lightemitting elements include a light reflection layer, a light emittinglayer, and a first light transparent layer, the respective lightemitting layers of the first, second, and third light emitting elementsextending throughout the plurality of light emitting elements, whereinin the first light emitting element, the light reflection layer isarranged at a first distance from the red region, in the second lightemission element, the light reflection layer is arranged at a seconddistance from the green region, and in the third light emission element,the light reflection layer is arranged at a third distance from the blueregion, wherein the first distance, the second distance and the thirddistance are different, and wherein a shape of the first light shieldinglayer and a shape of the second light shielding layer are different in across sectional view.
 2. The display device according to claim 1,wherein a distance between a lowermost surface of the first lightshielding layer and an uppermost surface of the first light shieldinglayer is different from a distance between a lowermost surface of thesecond light shielding layer and an uppermost surface of the secondlight shielding layer.
 3. The display device according to claim 1,wherein a distance between a lowermost surface of the first lightshielding layer and an uppermost surface of the first light shieldinglayer is longer than a distance between a lowermost surface of thesecond light shielding layer and an uppermost surface of the secondlight shielding layer.
 4. The display device according to claim 1,wherein the first light emitting element is adjacent to the second lightemitting element.
 5. The display device according to claim 1, wherein adistance between a first side surface of the first light shielding layerand a second side surface of the first light shielding layer isdifferent from a distance between a first side surface of the secondlight shielding layer and a second side surface of the second lightshielding layer.
 6. The display device according to claim 1, wherein adistance between a first side surface of the first light shielding layerand a second side surface of the first light shielding layer is longerthan a distance between a first side surface of the second lightshielding layer and a second side surface of the second light shieldinglayer.
 7. The display device according to claim 1, wherein a lowermostportion of a bottom of the first light shielding layer is different froma lowermost portion of a bottom of the second light shielding layer. 8.The display device according to claim 1, wherein the plurality of lightemitting elements further includes a fourth light emitting element, andthe color filter further comprises a transparent region corresponding tothe fourth light emitting element, wherein the fourth light emittingelement is configured to emit a white light.
 9. The display deviceaccording to claim 1, wherein each of the plurality of light emittingelements is configured to emit a white light.
 10. The display deviceaccording to claim 1, wherein the first light transparent layer islocated between the light reflection layer and the color filter.
 11. Thedisplay device according to claim 1, wherein the light reflection layerincludes aluminum, an aluminum alloy, a Ti/Al laminated structure,chromium, silver, a silver alloy, or a combination thereof, and thelight reflection layer is a metal layer.
 12. The display deviceaccording to claim 1, wherein a lowermost portion of a bottom of thefirst light shielding layer is lower than a lowermost portion of abottom of the second light shielding layer.
 13. The display deviceaccording to claim 1, wherein each of the first, second, and third lightemitting element further includes a second light transparent layer. 14.The display device according to claim 13, wherein the first lighttransparent layer is a cathode electrode and the second lighttransparent layer is an anode electrode.
 15. The display deviceaccording to claim 1, wherein the first light shielding layer has afirst portion and a second portion, the first portion has a firstheight, and the second portion has a second height different from thefirst height.